While my favorite OS by far remains the Mac OS, until I get my laptop fixed or replaced I'm using Linux on my PC hardware. Now, I'm a Windows expert, but I also know Unix, and I'm finding Ubuntu Linux to be a much more pleasant experience than Windows so far.
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If ye love wealth better than liberty, the tranquility of servitude than the animated contest of freedom, go from us in peace. May your chains sit lightly upon you, and may posterity forget that you were our countrymen! - Samuel Adams
I used it for quite awhile, but missed some applications (seems like Flash and/or Java wasn't working with Ubuntu). Then it started getting buggy, so I went back to Windows. But for awhile I really liked it.
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"There is order in the way the Lord reveals His will to mankind. . .we cannot receive revelation for someone else's stewardship." L. Tom Perry
Well, It's gotten better. Flash works just fine for me (my bank's website uses it heavily). For Windows programs I use Wine to run them. I still haven't tried it out with World of Warcraft, but I understand that it works pretty well.
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If ye love wealth better than liberty, the tranquility of servitude than the animated contest of freedom, go from us in peace. May your chains sit lightly upon you, and may posterity forget that you were our countrymen! - Samuel Adams